Mycology Vignettes 2008

(1) Lymphocutaneous sporotrichosis Sporothrix schenckii Scratched hand while working in garden center, infection spreading up arm Conidiospore formation on tip of slender conidiophores Dimorphism Grows faster at 30C Infection at wound site, lesion spread along draining lymphatics (sporotrichoid pattern) Dx: anti-Sporothrix Ab, PCR (if available) Tx: Itraconazole, amphotericin B if severe

(2) Tinea Versicolor Malassezia furfur Nonpainful lesions lack pigmentation, no inflammation Not leprosy b/c has normal pain sensation Normal skin flora, obligate lipophilic Yeast grows in clusters of near-spherical yeasts and some filamentous forms Dx: Wood’s light (near u.v.) fluoresce green-yellow, KOH stain

(3) Itchy Wresting Jock Tinea corporis, Tinea pedis, Erythrasma Wrestler has ring of inflamed skin on arm, flaking between toes, infection inside thigh Arm: Tinea corporis Foot: Tinea pedis Thigh: Erythrasma Tx: Itraconazole or terbinafine Arm near-spherical microconidia, zoophilic species Foot somewhat elongate miroconidia, Trichophyton rubrum Thigh fluoresce coral-red under Wood’s light, probably Corynebac-terium minutissimum

(4) Blastomycosis Blastomyces dermatitidis Vacation in MN Non-healing lesions on nose, arm, leg for 6 mo Pulmonary infiltrates Dx: Ab to “WI-1” or “A antigen” Bimorphic, near-spherical yeast which have a broad base to the bud Grows best at 30C Tx: Amphotericin B, Itraconazole, Fluconazole (if CNS)

(5) Coccidioidomycosis Coccidioides immitis/posadasii 20 yo M in hospital with pneumonia, meningitis with skin lesions on face Infected in the lung from disturbed soil Dx: nucleic acid probes specific for rRNA sequences Spherules mature in tissue and are packed with endospores Mold produces arthro-spores separated by empty cells Progressive disease are DTH skin test negative and high complement-fixing titers (IgG)

(6) Cryptococcosis Cryptococcus neoformans HIV+ home remodeler Poor mental status Lesions on forearm/butt Infected in the lungs Dx: Latex test for Cryptococcus capsular carbohydrate Pigeon droppings (C. gattii associated with eucalyptus trees, Vancouver) Budding yeast (india ink), brown colonies on bird seed agar Affects T-cell mediated immunodeficient

(7) Erythema nodosum/multiforme Coccidioides immitis Traveled in AZ, NV, exposed to dust Develop painful red bumps, warm, tender No evidence of infection when scraped on KOH mount Passenger developed rash Hypersensitivity rxn Multiple possible causes, location suggests C. immitis Adult women susceptible Tx: steroids (for stress-induced hives)

(8) Histoplasmosis Histoplasma capsulatum Recently emigrated bulder with influenza-like illness, lesions on finger/tongue Pulmonary infiltrates, severe lung disease Good prognosis: strong DTH, low CF Ab titer Two spore forms (large rough, small) Dimorphic, mycelium produces rough macroconidia and microconidia Blackbird feces and bat guano in soil and attics

(9) Aspergillosis/Zygomycosis 18 yo M treated for leukemia deveops pulmonary disease Likely infected by air, needs neutropenia Voriconazole is effective for aspergillis, but not zygomycetes Patient dies Not contagious Aspergillis: septate hyphae with 45⁰ branchs, characteristic conidiophores and conidia Zygomyces: irregular hyphae, few/no septa, mold grows sporangia

(10) Candidiasis Candida albicans 25 yo F with rash, soreness of thighs, vagina, mouth Dx: Yeasts with germ tubes, chlamydospores, pseudohyphae Associated with diabetes, AIDS, immunosuppression, poorly-fitting dentures Invasive disease associated with neutropenia

(11) Pneumonia, Meningitis, Catheter Inf (11) Pneumonia, Meningitis, Catheter Inf. Pneumocystis, Cryptococcus, Candida 22 yo F with SOB, confused, difficulty walking, oral thrush, severe pneumonia, nuchal rigidity, IV catheter infection Tx broad spectrum ATB and fluconazole (should add TMP-SMX) Probably HIV positive P. jiroveci are clumps of cysts in alveoli C. neoformans caused the meningitis, stains with india ink Candida species caused the catheter infection, pseudohyphae, budding yeast w/o germ tube